JP2007051983A - Encoder for rotation detection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure capable of securing reliability of a bonding part between an encoder body 13b and a support ring 12b, which is a structure wherein the encoder body 13b and the support ring 12b are bonded together. <P>SOLUTION: The encoder body 13b is formed by insert molding for sending a polymer material intermingled with a magnetic material into a cavity, in the state where the support ring 12b is set into the cavity of a die for injection molding. Then, the encoder body 13b and the support ring 12b are bonded in a body. Protrusions 20, 20 formed on the outer circumferential surface of an outer diameter side cylindrical part 15 constituting the support ring 12b are engaged in the ridged/grooved state with recessed grooves 21, 21 on the inner circumferential surface of the encoder body 13b, to thereby prevent relative rotation between the encoder body 13b and the support ring 12b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The rotation detection encoder according to the present invention is used in a state of being fitted and fixed to a hub that is a rotating member, for example, in order to obtain the direction and magnitude of a load acting on a rolling bearing unit for supporting a wheel of an automobile.

  For example, a rolling bearing unit is used to rotatably support a vehicle wheel with respect to a suspension device. Moreover, in order to ensure vehicle running stability, vehicle running state stabilizing devices such as an antilock brake system (ABS), a traction control system (TCS), and an electronically controlled vehicle running stabilizer (ESC) are widely used. in use. According to these running state stabilizing devices such as ABS and TCS, the running state of the vehicle at the time of braking or acceleration can be stabilized, but in order to ensure this stability even under more severe conditions, the vehicle It is necessary to control the brakes and the engine by incorporating more information that affects the running stability of the vehicle.

  That is, in the case of the conventional running state stabilizing device such as ABS or TCS, since so-called feedback control is performed to detect the slip between the tire and the road surface and control the brake and the engine, the brake and engine Control is delayed for a moment. In other words, in order to improve performance under severe conditions, the so-called feed-forward control prevents slippage between the tire and the road surface, or the so-called brake one-side effect where the braking forces of the left and right wheels are extremely different. Cannot be prevented. Furthermore, it is impossible to prevent the running stability of a truck or the like from being deteriorated based on the poor loading state.

  In order to cope with such a problem, in order to perform the feedforward control or the like, one of a radial load and an axial load applied to the wheel is applied to the rolling bearing unit for supporting the wheel with respect to the suspension device. Or it is possible to incorporate a load measuring device for measuring both. Conventionally, what was described in patent documents 1-4 is known as a rolling bearing unit for wheel support with a load measuring device which can be used in such a case.

  Of these, Patent Document 1 describes a rolling bearing unit with a load measuring device capable of measuring a radial load. In the case of the first example of the conventional structure, the outer ring and the hub are measured by measuring the radial displacement between the outer ring that does not rotate and the hub that rotates on the inner diameter side of the outer ring by a non-contact displacement sensor. The radial load applied between and is calculated. The obtained radial load is used not only to properly control the ABS but also to inform the driver of a bad loading condition.

  Patent document 2 describes a structure for measuring an axial load applied to a rolling bearing unit. In the case of the second example of the conventional structure described in Patent Document 2, bolts for connecting the fixed side flange to the knuckle are screwed at a plurality of positions on the inner side surface of the fixed side flange provided on the outer peripheral surface of the outer ring. Each load sensor is attached to a portion surrounding the screw hole. Each load sensor is clamped between the outer surface of the knuckle and the inner surface of the fixed flange in a state where the outer ring is supported and fixed to the knuckle. In the case of the load measuring device for the rolling bearing unit of the second example having such a conventional structure, the axial load applied between the wheel and the knuckle is measured by the load sensors.

  Further, in Patent Document 3, the displacement sensor unit supported at four positions in the circumferential direction of the outer ring and the L-shaped detection ring that is externally fitted and fixed to the hub are used to detect the above-described outer ring at the four positions. A structure is described in which the displacement of the hub in the radial direction and the axial direction is detected, and the direction of the load applied to the hub and the magnitude thereof are determined based on the detection values of the respective parts.

  Furthermore, in Patent Document 4, a strain gauge for detecting dynamic strain is provided in a member corresponding to an outer ring whose rigidity is partially reduced, and the revolution speed of the rolling element is determined from the passing frequency of the rolling element detected by the strain gauge. A method for determining the axial load applied to the rolling bearing from the revolution speed is described.

  In the case of the first example of the conventional structure described in Patent Document 1, the load applied to the rolling bearing unit is measured by measuring the displacement in the radial direction between the outer ring and the hub using a displacement sensor. However, since the displacement amount in the radial direction is small, it is necessary to use a highly accurate displacement sensor in order to obtain this load with high accuracy. Since high-precision non-contact sensors are expensive, it is inevitable that the cost of the entire rolling bearing unit with a load measuring device increases.

  In the second example of the conventional structure described in Patent Document 2, it is necessary to provide as many load sensors as the bolts for supporting and fixing the outer ring to the knuckle. For this reason, coupled with the fact that the load sensor itself is expensive, it is inevitable that the cost of the entire load measuring device of the rolling bearing unit is considerably increased. In addition, the structure described in Patent Document 3 is more expensive than the structure described in Patent Document 1 because sensors are installed at four positions in the circumferential direction of the outer ring. Furthermore, the method described in Patent Document 4 needs to reduce the rigidity of a part of the outer ring equivalent member, and it may be difficult to ensure the durability of the outer ring equivalent member.

  In view of such circumstances, Japanese Patent Application No. 2004-279155 measures the magnitude of the load applied to the rolling bearing unit based on the phase difference between the output signals of a pair of sensors arranged in the direction of the load. An invention relating to a load measuring device for a wheel bearing rolling bearing unit is disclosed. 19 to 27 show the structure of three examples of the prior invention disclosed in the above application. As shown in FIGS. 19, 23, and 26, each of the structures according to the respective prior inventions supports and fixes the wheel on the inner diameter side of the outer ring 1 that is a stationary side race ring that does not rotate while being supported by the suspension device. A hub 2 that is a rotating side race ring (coupled and fixed) is rotatably supported via a plurality of rolling elements 3 and 3.

  In the case of the structure of the first example shown in FIGS. 19 to 22, the encoder 4 is fitted and fixed to the intermediate portion of the hub 2. Further, a pair of sensors 5 and 5 are disposed between the rolling elements 3 and 3 arranged in a double row at the axially intermediate portion of the outer ring 1, and each detection unit is a surface to be detected. The encoder 4 is provided so as to be close to and opposed to the outer peripheral surface of the encoder 4. In addition, magnetic detection elements such as a Hall IC, a Hall element, an MR element, and a GMR element are incorporated in the detection portions of the sensors 5 and 5.

  In the case of the structure of the first example of the previous invention, the encoder 4 is made of a permanent magnet. On the outer peripheral surface of the encoder 4 which is a detection surface, portions magnetized in the N pole and portions magnetized in the S pole are alternately arranged at equal intervals in the circumferential direction. The boundary between the part magnetized in the N pole and the part magnetized in the S pole is inclined by the same angle with respect to the axial direction of the encoder 4, and the inclination direction with respect to the axial direction of the encoder 4 is The axial directions are opposite to each other at the intermediate portion. Therefore, the portion magnetized in the N pole and the portion magnetized in the S pole have a “<” shape with the axially middle portion protruding (or recessed) most in the circumferential direction.

  The positions where the detection parts of the sensors 5 and 5 face the outer peripheral surface of the encoder 4 are the same with respect to the circumferential direction of the encoder 4. In other words, the detection parts of the sensors 5 and 5 are arranged on the same virtual plane including the central axis of the outer ring 1. Further, in the state where the axial load is not applied between the outer ring 1 and the hub 2, the axial direction intermediate portion between the portion magnetized in the N pole and the portion magnetized in the S pole is related to the circumferential direction. The installation positions of the members 4, 5, and 5 are regulated so that the most protruding part (the part in which the tilt direction of the boundary changes) is exactly at the center position between the detection parts of the sensors 5 and 5. is doing. In this way, by making the portion where the inclination direction of the boundary changes in the center position, errors due to temperature difference between the inner and outer rings and deformation due to thermal expansion (even if no displacement occurs, the temperature difference between the inner and outer rings The so-called offset, which causes a phase difference, can be kept small.

  In the case of the first example of the prior invention configured as described above, when an axial load is applied between the outer ring 1 and the hub 2, the phase at which the output signals of the sensors 5, 5 change is shifted. That is, in the neutral state where an axial load is not applied between the outer ring 1 and the hub 2 and the outer ring 1 and the hub 2 are not relatively displaced, the detecting portions of the sensors 5 and 5 are , On the solid lines a and b in FIG. 22A, that is, opposite to the most protruding portion in the axial direction by the same amount. Accordingly, the phases of the output signals of the sensors 5 and 5 coincide as shown in FIG.

  On the other hand, when a downward axial load acts on the hub 2 to which the encoder 4 is fixed in FIG. 22A (the outer ring 1 and the hub 2 are relatively displaced in the axial direction), The detection parts of the sensors 5 and 5 are opposed to the broken lines B and B in FIG. 22A, that is, the parts different from each other in the axial direction from the most protruding part. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG. Further, when an upward axial load is applied to the hub 2 to which the encoder 4 is fixed as shown in FIG. 22A, the detecting portions of both the sensors 5 and 5 are connected to the chain line H shown in FIG. , C, that is, the deviation in the axial direction from the most projecting portion opposes different portions in the opposite direction. In this state, the phases of the output signals of the sensors 5 and 5 are shifted as shown in FIG.

  As described above, in the case of the first example of the prior invention, the phases of the output signals of the sensors 5 and 5 are shifted in the direction corresponding to the direction of the axial load applied between the outer ring 1 and the hub 2. Further, the degree to which the phase of the output signals of the sensors 5, 5 is shifted by this axial load (displacement amount) increases as the axial load increases. Therefore, in the case of the first example, based on the presence and absence of the phase shift of the output signals of the sensors 5 and 5 and the direction and magnitude of the shift, between the outer ring 1 and the hub 2. The direction and magnitude of the acting axial load can be determined.

  Next, in the case of the second example of the prior invention shown in FIGS. 23 to 25, the S pole and the N pole are provided on the outer peripheral surface which is the detected surface of the encoder 4 a that is externally fitted and fixed to the intermediate portion of the hub 2. They are arranged alternately and at equal intervals. The boundary between the S pole and the N pole adjacent in the circumferential direction is inclined with respect to the axial direction of the hub 2. The direction in which each boundary is inclined with respect to the radial direction is alternately opposite to the circumferential direction. Therefore, the part magnetized in the S pole and the part magnetized in the N pole each have a trapezoidal shape. And the detection part of the sensor 5a supported by this outer ring 1 in the state which penetrates the intermediate part of the outer ring 1 in the radial direction is made to oppose the outer peripheral surface of the encoder 4a as mentioned above.

  In the structure of the second example of the prior invention configured as described above, when an axial load is not acting between the outer ring 1 and the hub 2, the sensor 5a is rotated along with the rotation of the hub 2. The detection unit scans the axial center position indicated by the chain line α in FIG. At the center position in the axial direction, the widths of the S pole and the N pole in the rotation direction are equal to each other, so that the amplitude of the output signal of the sensor 5a is symmetrical about the zero point as shown in FIG. Become. On the other hand, when an axial load in a predetermined direction is applied between the outer ring 1 and the hub 2, the detection unit of the sensor 5 a moves along the axis indicated by the chain line β in FIG. 25 as the hub 2 rotates. Scan a position closer to one side in the direction. At this position closer to one side, the width of the S pole in the rotational direction is larger than the width of the N pole, so that the output signal of the sensor 5a is asymmetric in a predetermined direction with respect to the zero point as shown in FIG. Become. Further, when an axial load in the direction opposite to the predetermined direction is applied between the outer ring 1 and the hub 2, the detection unit of the sensor 5 a moves along a chain line γ in FIG. 25 as the hub 2 rotates. The indicated position on the other side in the axial direction is scanned. At the position closer to the other side, since the width of the S pole in the rotation direction is smaller than the width of the N pole, the output signal of the sensor 5a is asymmetric in the direction opposite to the predetermined direction with respect to the zero point. Therefore, the direction and magnitude of the axial load acting between the outer ring 1 and the hub 2 can be obtained based on the pattern of the output signal.

  Furthermore, in the case of the third example of the prior invention described in FIGS. 26 to 27, the encoder 4 b is externally fixed to the inner end portion of the hub 2. The encoder 4b is composed of a support ring 6 made of a magnetic metal plate and having a generally J-shaped cross section, and an encoder body 7 made of a permanent magnet and made of a ring. The encoder body 7 is attached to the inner surface in the axial direction of an annular support plate portion 8 provided at the inner end of the support ring 6 over the entire circumference, and is a shaft that is a detected surface. S poles and N poles are alternately arranged at equal intervals on the inner side surface in the direction. The boundary between the S pole and the N pole adjacent in the circumferential direction is inclined with respect to the radial direction of the encoder body 7. The direction in which each boundary is inclined with respect to the radial direction is alternately opposite to the circumferential direction. Therefore, the part magnetized to the S pole and the part magnetized to the N pole are respectively trapezoidal or fan-shaped. And the detection part of the sensor 5b supported by the cover 9 fitted and fixed to the inner end part of the outer ring 1 is made to face the detection surface of the encoder 4b as described above.

  In the structure of the third example of the prior invention configured as described above, when the radial load acting between the outer ring 1 and the hub 2 is a standard value, the sensor is accompanied with the rotation of the hub 2. The detection unit 5b scans the radial center position indicated by the chain line α in FIG. At the radial center position, the widths of the S pole and the N pole in the rotation direction are equal to each other, so that the output signal of the sensor 5b has the same ratio between the high potential and the low potential. On the other hand, when the radial load becomes larger than the standard value, the detection unit of the sensor 5b scans the position closer to the inner diameter indicated by the chain line β in FIG. 27 as the hub 2 rotates. At the position closer to the inner diameter, since the width of the S pole in the rotation direction is larger than the width of the N pole, the ratio of the high potential to the low potential shifts in a predetermined direction in the output signal of the sensor 5b. Further, when the radial load becomes smaller than the standard value, the detection unit of the sensor 5b scans the position near the outer diameter indicated by a chain line γ in FIG. 27 as the hub 2 rotates. At the position closer to the outer diameter, the width of the S pole in the rotation direction is smaller than the width of the N pole, so that the output signal of the sensor 5b is shifted in the direction opposite to the predetermined direction. Therefore, the radial load acting between the outer ring 1 and the hub 2 can be obtained based on the pattern of the output signal.

  For example, the encoders 4, 4 a, and 4 b constituting the load measuring device for the wheel bearing rolling bearing unit as described above must be made of permanent magnets and securely fitted and fixed to the hub 2. As the permanent magnet, a rubber magnet or a plastic magnet in which a powder or fiber made of a magnetic material such as ferrite, iron powder or iron fiber is mixed in a polymer material such as rubber or synthetic resin can be preferably used. However, such rubber magnets or plastic magnets do not necessarily have sufficient toughness. For this reason, as shown in FIG. 28, it is difficult to externally fix the encoder body 7a made of a permanent magnet directly to the rotating body 10 by an interference fit. Therefore, in the actual case, as described in FIGS. 20, 23, 24 and 26, the encoders 4, 4a and 4b are supported by an encoder body made of a permanent magnet and a magnetic metal plate such as a mild steel plate. It is conceivable to adopt a structure in which the support ring is externally fixed by an interference fit to a rotating body such as a hub.

  However, even when the encoder is composed of the encoder body and the support ring in this way, it is necessary to adopt a structure that can ensure the joining strength between the encoder body and the support ring and the durability of the joint portion. . As a structure for joining the encoder body and the support ring, generally, a structure in which the encoder body and the support ring which are separately manufactured are bonded with an adhesive is conceivable. However, for example, in the case of a rolling bearing unit for supporting a wheel, the temperature may become considerably high during use due to heat generated in the brake portion. For this reason, since the adhesive may deteriorate and the joint portion between the encoder body and the support ring may be peeled off, the load measuring device for the rolling bearing unit for supporting the encoder and the wheel incorporating the encoder is incorporated. It is difficult to ensure reliability.

JP 2001-21577 A Japanese Patent Laid-Open No. 3-209016 Japanese Patent Laid-Open No. 2004-3918 Japanese Patent Publication No.62-3365

  In view of the circumstances as described above, the present invention is a structure in which an encoder body and a support ring are joined, and an invention for realizing a rotation detection encoder capable of ensuring the reliability of the joint portion between the encoder body and the support ring is provided. It is a thing.

The encoder for detecting rotation of the present invention is made of a magnetic material as a whole in an annular shape, a support ring that is fitted and fixed to a part of a rotating member whose rotational state is to be detected, and a magnetic material in a polymer material. The encoder body is made of a permanent magnet mixed with a material, and is attached to a part of the support ring over the entire circumference. The encoder body has S poles and N poles alternately arranged on the detection surface.
In particular, in the rotation detecting encoder of the present invention, the encoder body is a polymer material in which the magnetic material is mixed in the cavity in a state where the support ring is set in the cavity of an injection mold. Are integrally coupled to the support ring by insert molding.

  As described above, in the case of the rotation detection encoder of the present invention, the encoder body and the support ring are joined together with the injection molding of the encoder body. Because a primer for improving the joint strength is interposed in the joint (the primer is applied to the support ring prior to setting in the cavity), but it is auxiliary. Even if the temperature rises, the strength of the joint can be sufficiently secured.

In the case of carrying out the present invention, preferably, as described in claim 2, a concave and convex engaging portion in the circumferential direction is provided on the joint surface between the support ring and the encoder body. For this purpose, projections (including protrusions) or notches (including grooves) are formed on the surface of the support ring where the encoder body is joined.
In the case of the rotation detection encoder of the present invention, the joint between the encoder body and the support ring is basically brought into close contact with the encoder body by injection molding. The frictional force acting on Therefore, the encoder body and the support ring rotate relative to each other due to a decrease in contact surface pressure between the contact surfaces due to a difference in thermal expansion between the encoder body and the support ring due to a temperature change. We cannot deny the possibility of doing. On the other hand, if the concave and convex engaging portion is provided on the joint surface as described above, the encoder body and the support ring rotate relative to each other even when the contact surface pressure between the contact surfaces decreases. You can prevent things.

  Further, when the structure described in claim 2 is implemented, preferably, as described in claim 3, the number of concave and convex engaging portions existing on the joint surface and the detected surface of the encoder body are present. When the other number is viewed on the basis of either one of the numbers of the S pole and the N pole, an integer multiple relationship is provided. In this case, the relationship of integral multiples is the case where the number of the concave / convex engaging portions is equal to the number of S poles and N poles (the total number of poles of S poles and N poles). Either the number of parts is an integral multiple of the number of S poles and N poles, or the number of S poles and N poles is an integer multiple of the number of concave / convex engaging parts.

Such a structure described in claim 3 can prevent the magnetic flux density entering and exiting the detected surface of the encoder from changing irregularly with respect to the rotation direction, and the rotation of the rotary member with the encoder fitted and fixed thereto. Detection can be performed with high accuracy. The reason is as follows.
Even when the uneven engaging portion is provided, the detected surface is not uneven. That is, the detected surface remains a cylindrical surface (when the detected surface is an outer peripheral surface) or a flat surface (when the detected surface is an axial side surface). Accordingly, the thickness of the encoder body made of a permanent magnet is different from the other portions at the portion corresponding to the concave-convex engaging portion, and the magnetic flux density of the corresponding portion is different from the magnetic flux density of the other portion. It will be different. Such different directions (higher or lower) differ depending on the absolute thickness and magnetizing strength of the encoder body. As a general trend, when the absolute thickness is large, when the magnetizing strength is strong, there is a protrusion on the side of the support ring, and the thickness of the encoder body is small at the concave / convex engagement part In addition, the magnetic flux density is increased at the portion of the detected surface corresponding to the concave / convex engaging portion. On the contrary, when the absolute thickness is small, when the magnetizing strength is weak, there is a protrusion on the side of the support ring, and when the thickness of the encoder body is small at the concave / convex engaging portion, In the detection surface, the magnetic flux density is lowered at the portion corresponding to the uneven engagement portion.

  In any case, it is difficult to avoid a state in which the magnetic flux density is different from other portions in a part of the detected surface of the encoder in the circumferential direction with the provision of the concave and convex engaging portion. Then, when such a portion having a different magnetic flux density appears regardless of the S and N poles arranged on the detected surface, the change in the output signal of the sensor having the detecting portion opposed to the detected surface of the encoder And the rotation of the encoder are less likely to have a relationship, and the rotation state of the rotating member that externally supports the encoder cannot be obtained accurately. On the other hand, if there is an integer multiple relationship between the number of the concave and convex engaging portions and the number of the S and N poles, the magnetic flux density is different from that of the other portions corresponding to the concave and convex engaging portions. A different part appears in a state having relevance to the south pole and the north pole arranged on the detection surface. For this reason, it becomes easy to have a relationship between the change period of the output signal of the sensor having the detection unit opposed to the detection surface of the encoder and the rotation of the encoder, and the rotating member that externally supports the encoder. The rotation state can be accurately obtained.

  In addition, when the number of the S poles and the N poles is an integer multiple (two or more) of the number of the concave and convex engaging portions, the pole having the concave and convex engaging portions among these S and N poles. And a pole that does not exist. Therefore, when the magnetic flux density varies depending on the poles and no measures are taken, there is a possibility that the rotational state of the rotating member that externally supports the encoder cannot be obtained accurately. Specifically, depending on the threshold value set in the processing circuit for processing the detection signal of the sensor, it is impossible to accurately measure the pitch between the S pole and the N pole existing on the detected surface of the encoder (pitch error). Produce). However, since the pitch error generated in this way has a periodicity of one period with respect to one rotation of the encoder, it is possible to remove the influence by filter processing such as an adaptive filter or a notch filter. Therefore, a structure in which the number of the S poles and the N poles is an integral multiple of the number of the concave and convex engaging portions can also be used as a countermeasure for the change in magnetic flux density due to the concave and convex engaging portions.

  Further, when carrying out the invention described in claim 3 as described above, preferably, as described in claim 4, the phase of the concavo-convex engagement portion is set on a part of the support ring in the circumferential direction. An indicator for identifying is provided. As such an indicator portion, a concave portion or a convex portion formed in a portion of the support ring that is not covered by the encoder body can be preferably used. Such a concave portion or convex portion engages with a convex portion or a concave portion provided in a magnetizing device for magnetizing the encoder body, and a projection formed on the support ring with respect to the magnetizing yoke of the magnetizing device or Regulate the phase of the notch. Therefore, in a state in which the encoder body is magnetized by the magnetizing yoke, the phases of the S pole and N pole and the protrusions or notches in the rotation direction of the encoder body are always constant (the most preferable state). it can. Therefore, the change state of the detection signal of the sensor based on the distribution state of the magnetic flux density on the detection surface of the encoder can be changed into a preferable form that can be easily processed by the processing circuit, and the rotation of the rotating member with the encoder fixedly fitted is fixed. This is advantageous in terms of accurate detection.

  1 to 3 show a first embodiment of the present invention corresponding to claim 1 only. The rotation detection encoder 11 of this embodiment includes a support ring 12 and an encoder body 13. Of these, the support ring 12 has an annular shape as a whole by bending a magnetic metal plate such as a mild steel plate by plastic working such as drawing or by turning a magnetic material such as carbon steel. Made. The support ring 12 is a cross-sectional crank type in which an axial end portion of the inner diameter side cylindrical portion 14 and an axial end portion of the outer diameter side cylindrical portion 15 arranged concentrically with each other are continued by an annular continuous portion 16. Thus, the whole is formed in an annular shape. In use, the inner diameter side cylindrical portion 14 is externally fixed to the outer peripheral surface of the intermediate portion of the rotating member 17 by an interference fit, and the outer diameter side cylindrical portion 15 is supported concentrically with the rotating member 17.

  On the other hand, the encoder body 13 is coupled and fixed to the outer peripheral surface of the outer diameter side cylindrical portion 15 over the entire circumference. The encoder body 13 is made of a permanent magnet in which a magnetic material such as ferrite, iron powder, or iron fiber is mixed in a polymer material such as rubber or synthetic resin, and an S pole is formed on the outer peripheral surface that is a detection surface. And N poles are alternately arranged at equal intervals. The shape of the magnetized region of each pole is arbitrary, but for example, it is a “<” shape as shown in FIG. 2A or a trapezoid as shown in FIG. Of these, (A) corresponds to the structure of the first example of the prior invention shown in FIGS. 19 to 22, and (B) corresponds to the structure of the second example shown in FIGS.

  In the encoder body 13 as described above, the support ring 12 is set in a cavity of a mold for injection molding the encoder body 13, and a polymer material in which the magnetic material is mixed in the cavity is formed. Formed by feeding. Thus, by performing insert molding in which a polymer material is fed into the cavity in which the support ring 12 is set, the support ring 12 and the encoder body 13 immediately after injection molding are integrally coupled. The magnet body 13 is magnetized by removing the support ring 12 and the encoder body 13 from the cavity and then setting the encoder body 13 in a separately provided magnetizing device. After the magnetization, the magnetic flux density on the outer peripheral surface of the encoder body 13 changes in a sine wave shape in the circumferential direction as shown in FIG.

  As described above, in the case of the rotation detection encoder 11 of this embodiment, the encoder body 13 and the support ring 12 are joined together with the injection molding of the encoder body 13. Prior to setting the support ring 12 in the cavity, a primer applied to the outer peripheral surface of the outer diameter side cylindrical portion 15 may be present on the joint surface of the encoder body 13 and the support ring 12. However, since it is a supplementary thing, even if it is a case where temperature rises, the intensity | strength of the said junction part is fully securable. For this reason, the encoder 11 for rotation detection which can ensure the reliability of the junction part of these encoder main bodies 13 and the support ring 12 by the structure which joined the said encoder 13 and the said support ring 12 is realizable.

FIG. 4 also shows a second embodiment of the present invention corresponding to claim 1 only. The support ring 12a that constitutes the rotation detecting encoder 11a of the present embodiment is composed of a cylindrical portion 18 and an annular portion 19 that is bent radially outward from the axial end of the cylindrical portion 18. Thus, the whole is formed in an annular shape. Then, an annular encoder body 13a made of a permanent magnet is attached and supported on one side surface in the axial direction of the annular ring portion 19 over the entire circumference. On one side surface in the axial direction, which is the detection surface of the encoder body 13a, the S poles and the N poles are alternately arranged in the circumferential direction, for example, in a pattern as shown in FIG.
The configuration and operation of the other parts are the same as in the case of the first embodiment.

  5 to 6 show a third embodiment of the present invention corresponding to claims 1 to 4. As shown in FIG. 5A, the support ring 12b constituting the rotation detecting encoder 11b of the present embodiment performs plastic working such as forging or cutting work on a magnetic metal material such as carbon steel. As a result, the whole is formed in an annular shape with a cross-sectional crank type. In particular, in the case of the present embodiment, a plurality of long ridges 20 and 20 that are long in the axial direction are arranged at equal intervals in the circumferential direction on the outer peripheral surface of the outer diameter side cylindrical portion 15 constituting the support ring 12b. Forming.

  The encoder main body 13b which constitutes the rotation detecting encoder 11b together with the support ring 12b is a polymer in which the support ring 12b is set in the cavity of the injection mold and a magnetic material is mixed in the cavity. It is formed by feeding materials. In the state in which the polymer material is cooled and solidified, as shown in FIG. 5B, the protrusions 20 and 20 on the support ring 12b side are formed inside the encoder body 13b along with injection molding (insert molding). Each of the grooves formed on the peripheral surface engages with concave and convex grooves 21 and 21 that are long in the axial direction. Therefore, the encoder 13b is reliably prevented from rotating with respect to the support ring 12b.

  In the present embodiment, the number of protrusions 20 and 20 on the support ring 12b side and the number of S poles and N poles existing on the outer peripheral surface of the encoder 13b are made equal to each other. Further, the phase of each of the protrusions 20 and 20 and the phase of the S pole and the N pole in the rotation direction of the rotation detecting encoder 11b are matched. Specifically, each of the protrusions 20 and 20 is located in the circumferential center of the S pole and the N pole. For this reason, in the case of the present embodiment, each of the protrusions 20 and 20 is formed on a part of the support ring 12b in the circumferential direction, for example, on the distal end edge of the inner cylindrical portion 14 or the side surface of the continuous portion 16. An indicator portion (not shown) for identifying the phase is provided. The index portion regulates the phase of the support ring 12b in the circumferential direction with respect to the magnetized yoke, and the encoder body 13b is magnetized by the magnetized yoke so that the center of the S and N poles is centered. The protrusions 20 and 20 are positioned on the portion.

As a result, in the case of the present embodiment, the change in the magnetic flux density based on the existence of each of the protrusions 20 and 20 appears regularly at each period as shown by the chain line in FIG. 6 (the maximum value of the change). And affects the direction of increasing the minimum value). For this reason, the change state of the detection signal of the sensor based on the distribution state of the magnetic flux density on the outer peripheral surface of the rotation detection encoder 11b can be changed to a preferred form that can be easily processed by the processing circuit. This is advantageous from the standpoint of accurately detecting the rotation of the rotating member fitted and fixed to the rotation detecting encoder 11b.
The configuration and operation of the other parts are the same as in the case of the second embodiment described above.
Incidentally, when the phase in the circumferential direction of the support ring 12b with respect to the magnetized yoke is not restricted, for example, as shown in FIG. 7, the change in magnetic flux density due to the presence of the protrusions 20 and 20 is However, it does not always appear that the sensor signal processing is easily performed.

8 to 9 show a fourth embodiment of the present invention corresponding to claims 1 to 4. The outer peripheral surface of the outer diameter side cylindrical portion 15 of the support ring 12c constituting the rotation detecting encoder 11c of the present embodiment is an integral multiple (two times) the number of S poles and N poles existing on the outer peripheral surface of the encoder body 13c. ) And the ridges 20 and 20 are formed. For this reason, the magnetic flux density distribution of the rotation detecting encoder 11c of the present embodiment has a shape in which the maximum value and the minimum value of the change are increased at two locations for each pole, as shown by a chain line in FIG.
The configuration and operation of the other parts are the same as in the case of the third embodiment described above.

10-11 has shown Example 5 of this invention corresponding to Claims 1-4. The number of S poles and N poles existing on the outer peripheral surface of the encoder main body 13d constituting the rotation detecting encoder 11d of the present embodiment is similarly set to the ridge 20 existing on the outer peripheral surface of the outer diameter side cylindrical portion 15 of the support ring 12d. , 20 is an integer multiple (2 times) of the number. For this reason, the distribution of magnetic flux density of the rotational speed detecting encoder 11d of this embodiment has a shape in which the maximum value and the minimum value of the change are increased for each one of the poles as shown by a chain line in FIG. . Even if the magnetic flux density changes as shown in FIG. 11, if the threshold value of the circuit for processing the detection signal of the sensor that changes in accordance with the magnetic flux density is appropriately set, the rotation detection encoder The rotation state of the rotary member with 11d fitted and fixed can be accurately obtained.
The configuration and operation of the other parts are the same as those in the third embodiment and the fourth embodiment described above.

12 to 13 show a sixth embodiment of the present invention corresponding to claims 1 to 4. The number of S poles and N poles existing on the outer peripheral surface of the encoder main body 13e constituting the rotation detecting encoder 11e of the present embodiment is similarly set to the protrusion 20 existing on the outer peripheral surface of the outer diameter side cylindrical portion 15 of the support ring 12e. , 20 times the number. For this reason, the distribution of the magnetic flux density of the rotation detecting encoder 11e of this embodiment increases the maximum value and the minimum value for every other one of the poles, as shown by the chain line in FIG. Become a shape. Even in the shape of the change in magnetic flux density as shown in FIG. 13, the threshold value of the circuit that processes the detection signal of the sensor that changes in accordance with the magnetic flux density is set as in the case of the fifth embodiment. If set appropriately, the rotation state of the rotating member with the rotation detecting encoder 11d fitted and fixed can be accurately obtained.
The configuration and operation of the other parts are the same as those of the third and fourth embodiments and the fifth embodiment.

  FIG. 14 shows Embodiment 7 of the present invention corresponding to claims 1 to 4. In the case of the present embodiment, the relative rotation between the support ring 12f constituting the rotation detection encoder 11f and the encoder main body 13f has a structure in which the detected surface is one side surface in the axial direction as shown in FIG. In order to prevent this, long radial ridges 20a, 20a are formed on one side surface in the axial direction of the annular ring portion 19 constituting the support ring 12f. About the relationship between the number of these protrusions 20a and 20a and the number of S poles and N poles, it is the same as that of the case of Example 5 shown in FIGS.

  FIG. 15 shows an eighth embodiment of the present invention corresponding to the first to fourth embodiments. In the case of the present embodiment, in order to prevent relative rotation between the support ring 12g constituting the rotation detecting encoder 11g and the encoder main body 13g, the outer circumferential surface of the outer diameter side cylindrical portion 15 constituting the support ring 12g Each of them forms a groove 21a, 21a that is long in the axial direction. The protrusions 20b and 20b formed on the inner peripheral surface of the encoder main body 13g are engaged with each other along with injection molding to prevent relative rotation between the support ring 12g and the encoder main body 13g. The configuration and operation of other parts such as the relationship between the number of the protrusions 20b and 20b and the number of S poles and N poles are the same as those of the third embodiment shown in FIGS. .

  The shape of the ridge or the groove formed on the outer peripheral surface of the outer diameter side cylindrical portion of the support ring constituting the present invention is not limited to the above-described one. For example, as shown in FIG. 16, short ridges 20 b and 20 b that do not reach the tip end edge of the outer diameter side cylindrical portion, and ridges 20 c and 20 c that are semicircular in cross section as shown in FIG. It is also possible to adopt the concave grooves 21b and 21b having a semicircular cross section as shown in FIG.

Sectional drawing which shows Example 1 of this invention in the assembly | attachment state to a rotating member. FIG. 3 is a development view showing two examples of a magnetization pattern on an outer peripheral surface. The diagram which shows magnetic flux distribution regarding the circumferential direction. Sectional drawing which shows Example 2 of this invention in the assembly | attachment state to a rotating member. Embodiment 3 of the present invention is shown, in which (A) shows a support ring, and (B) shows a state where an encoder for rotation detection is formed by combining this support ring and an encoder body. (a) is a view seen from the axial direction, and (b) is a view cut from a part and seen from above (a). The diagram which shows magnetic flux distribution regarding the circumferential direction. A diagram showing an undesirable magnetic flux distribution. The figure similar to FIG. 5 which shows Example 4 of this invention. The diagram which shows magnetic flux distribution regarding the circumferential direction. The figure similar to FIG. 5 which shows Example 5 of this invention. The diagram which shows magnetic flux distribution regarding the circumferential direction. The figure similar to FIG. 5 which shows Example 6 of this invention. The diagram which shows magnetic flux distribution regarding the circumferential direction. FIGS. 7A and 7B show Embodiment 7 of the present invention, where FIG. 7A shows a support ring, and FIG. 7B shows a state where an encoder main body is assembled to the support ring. FIG. Similarly, (b) is an X-O-Y cross-sectional view of (a). The figure similar to FIG. 5 which shows Example 8 of this invention. The 1st example of another shape of a support ring is shown, (a) is a figure seen from the direction of an axis, and (b) is a figure which cut a part and was seen from the upper part of (a). The figure similar to FIG. 16 which shows the 2nd example. The figure similar to FIG. 16 which shows the 3rd example. Sectional drawing which shows the 1st example of the rolling bearing unit for wheel support with a load measuring device which concerns on a prior invention. The perspective view which takes out and shows the encoder incorporated in this 1st example. Similarly development. The schematic diagram for demonstrating the reason for which an axial load is calculated | required. Sectional drawing which shows the 2nd example of the rolling bearing unit for wheel support with a load measuring device which concerns on a prior invention. The perspective view which takes out the encoder incorporated in this 2nd example, and shows with the state of a raw material, and the state after completion. The schematic diagram for demonstrating the reason for which an axial load is calculated | required. Sectional drawing which shows the 3rd example of the rolling bearing unit for wheel support with a load measuring device which concerns on a prior invention. The figure which shows the state which took out the encoder and was seen from the right side of FIG. Sectional drawing which shows the state which carried out the external fitting fixation of the encoder main body directly to the rotary body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Hub 3 Rolling body 4, 4a, 4b Encoder 5, 5a, 5b Sensor 6, 6a Support ring 7, 7a Encoder main body 8 Support plate part 9 Cover 10 Rotating body 11, 11a, 11b, 11c, 11d, 11e, 11f, 11g Rotation detection encoder 12, 12a, 12b, 12c, 12d, 12e, 12f, 12g Support ring 13, 13a, 13b, 13c, 13d, 13e, 13f, 13g Encoder body 14 Inner diameter side cylindrical portion 15 Outer diameter side Cylindrical portion 16 Continuous portion 17 Rotating member 18 Cylindrical portion 19 Annular portion 20, 20a, 20b, 20c Projection 21, 21a, 21b Groove

Claims (4)

  Made of a magnetic material and made of a permanent magnet made entirely of an annular shape, a support ring that is fitted and fixed to a part of the rotating member whose rotation state should be detected by an interference fit, and a magnetic material mixed in a polymer material An encoder for rotation detection comprising an encoder body attached to a part of the support ring over the entire circumference and having S poles and N poles alternately arranged on the detection surface. Is integrally coupled to the support ring by insert molding in which a polymer material mixed with the magnetic material is fed into the cavity in a state where the support ring is set in a cavity of an injection mold. Rotation detection encoder characterized by this.   The rotation detecting encoder according to claim 1, wherein a concave and convex engaging portion in the circumferential direction is provided on a joint surface between the support ring and the encoder main body.   When the other number is viewed on the basis of one of the numbers between the number of concave / convex engaging portions present on the joint surface and the number of S poles and N poles present on the detected surface of the encoder body The rotation detection encoder according to claim 2, wherein an integer multiple relationship exists.   The rotation detecting encoder according to claim 3, wherein an index portion for identifying the phase of the concave-convex engaging portion is provided in a part of the support ring in the circumferential direction.

Images